Mechanism for carrying a transducer over an elongated path

ABSTRACT

A mechanism for bodily transporting a transducer over a closed, elongated path in which one portion of an arm is slidably coupled to a rotatable member. A transducer carrier attached to the arm is transported over a path defined by the composite motions of the two portions of the arm, thus carrying the transducer in a closed elongated loop.

United States Patent Hepner 1451 Dec. 5, 1972 [54] MECHANISM FORCARRYING A TRANSDUCER OVER AN ELONGATED PATII I [72] Inventor: NealHepner, Birmingham, Mich. [731 Assignee: Burroughs Corporation, Detroit,

Mich.

[22] Filed: Oct. 2, 1970 [211 Appl. No.: 77,450

[52'] us. CI .....74/47 [51] Int. Cl E1611 21/18 [58] Field of Search..74/47, 48, 45, 519, 473

[56] References Cited UNITED STATES PATENTS 288,778 11/1883 Davis..74/47 634,789 10/1899 Ambler ..74/47 851,731 4/1907 Daley ..74/47FOREIGN PATENTS OR APPLICATIONS 10,705 1/1953 Germany ..74/47 141,7696/1903 Germany ...74/47 Primary Examiner-Milton Kaufman AssistantExaminer-Wesley S. Ratlifi, Jr. Attorney-Kenneth L. Miller and Edwin W.Uren [57] ABSTRACT A mechanism for bodily transporting a transducer overa closed, elongated path in which one portion of an arm is slidablycoupled to a rotatable member. A transducer carrier attached to the armis transported over a path defined by the composite motions of the twoportions of the arm, thus carrying the transducer in a closed elongatedloop.

3 Claims, 6 Drawing Figures PKTENTEU BEE 5 I973 3.704.630

sum 1 UF- 3 FIGJ.

INVENTOR. NEAL HEPNER.

AGENT BACKGROUND OF THE'INVENTION order to use the old bank books forthenew automated procedures a portion of the books must be provided onwhich information can be electronically written and from whichinformation can be read; One solution is to attach a magnetic strip tothe cover of the old bank books for accommodating apparatus that alignsa readwrite transducer with the strip and moves one with respect to theother over the length of the strip.

The shape in which the magnetic strip is placed on the book isimportant, for if the strip were disposed in a straight line, the lengthof the strip and consequently the amount of information the strip couldcontain would be relatively small. If, instead, the strip were formed ofa circle and the transducer rotated from the center thereof, a provisionwould have to be made for costly lead connectionsto the rotatingtransducer. I

To avoid having to rotate the transducer over a circular path it couldrather be fixed to apparatus that would move it bodily about a circlefrom outside the intcrior thereof. Then, however, another problem can berecognized. Most magnetic transducers are designed to operate only incertain ranges of positions relative to their motion over a magneticmedium or strip. When a transducer is effectively fixed in positionrelative to a circular strip, then bodily rotated about the circle, thetransducer equally-takes up all positions relative to its motion andconsequently spends a significant amount of travel time outside itsoperative position range.

SUMMARY OF THE INVENTION In view of the problems described above, it isan object of the present invention to trace a closed path over which anon-rotatable magnetic transducer may be moved while maintaining thetransducer within its operative position range for a maximum period oftravel time.

It is another object of the invention to securely carry a transducerover said path.

It is still another object of the invention to transport a transducerthrough its operative position range at a nearly constant velocity.

The invention accomplishes these and other objects by combining a memberthat is rotatable about a stationary axis with an arm that has a rotatedportion pivotally coupled with the rotatable member. Another or guidedportion of the arm is engaged with a guide means that guides the armalong a predetermined path. The rotation of the rotatable membertransports a transducer carrier attached to the arm about a closed,elongated loop. The relationships between the length of the arm, theposition, height and angle of the transducer carrier with respect to thearm may be adjusted so that a path is traced having only a small sectionin which the transducer is positioned outside its operative positionrange and in which the velocity of the carrier over the operativesection of the path has a minimum variance.

BRIEF DESCRIPTION OF THE DRAWINGS Tofacilitate a more completeunderstanding of the invention a preferred embodiment will hereinafterbe described in connection with the drawings in which:

FIG. 1 is a front elevation of a preferred mechanism;

FIG. 2 is a front ,diagrammatical view of the mechanism showing twotraces each resulting from a carrier of different length;

FIG. 3 is a diagrammatically view of the mechanism showing two traceseach resulting from a guide in a different position;

FIG. 4 is a diagrammatical view of the mechanism showing two traces eachresulting from an arm of different length;

FIG. 5 is a diagrammatical view of the mechanism showing a traceresulting from a curved guide; and

FIG. 6 is a diagrammatical view of the mechanism showing twelve traceseach from a different carrier positioned at equally spaced angles withrespect to the arm. I

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawingswherein like reference characters designate identical elements in thevarious figures, and particularly to FIG. 1, an arm 10 has a cammingprojection or shaft 12 extending transversely from one end or guidedportion 14 thereof. The camming shaft 12 engages a guideor slot 16 in asupporting plate 18, the slot having a width slightly greater than thediameter of the shaft so that it may slide freely therein. The slot 16is disposed on a guide line 20 and spaced apart from a rotatable memberor crank 22. A rotated portion 24 of the arm is pivotally connected at apivot point 25 by means of a pivot shaft 26 to the rotatable crank 22,the crank being rigidly mounted to a crank shaft 28 projecting through abearing in the supporting plate 18. The crank shaft 28 is rotatableabout a stationary axis 30 and upon such rotation carries the crank withit in clockwise rotation.

A transducer carrier 32 is fixedly connected with the rotated portion 24of the arm 10 and extends normally therefrom. A free end 34 of thecarrier 32 is configured in an appropriate shape for supporting atransducer 36. With the transducer 36 mounted on the free end 34 of thecarrier 32, a rotation of the crank 22 causes the guided portion 14 ofthe arm 10 to reciprocally slide within the slot 16 and the rotatedportion 24 of the arm to rotate with the crank. The transducer 36 isconsequently carried in a path 38 that is characterized by the compositeof these two motions as altered by the geometry of the carrier 32.

OPERATION 3 vantageously be disposed a magnetic information-bearingstrip. As can be observed in FIG. I, the path 38 or trace of the freeend 34 of the carrier 32 has very short end portions 39 over which amounted transducer 36 tionships result in traces with undesirablecharac-,

teristics. Some of these various relationships will hereinafter bedescribed and their advantageous aspects as well as their undesirableones will be pointed out. The description will refer toones of FIGS. 2-6each of which are simplified diagrams similar to FIG. 1 in which thecarrier 32, arm and guide 16 are shown as dark lines and the circularpath of the crank 22 is illustrated by a dotted line.

Assuming that all other relationships remain constant, if the length ofthe transducer carrier 32 relative to the length of the arm 10 isincreased, the trace elongates, as shown in FIG. 2. As heretoforedescribed the elongated trace is preferable in that the end portionsthereof are very short in relation to the elongated portions where thetransducer 36 is transported in a position within its operative range.It has been found that when the carrier 32 and the arm 10 are disposedat right angles, as shown, thecarrier should be at least as long as thearm to provide a traceof sufficient elongation. As an example, FIG. 2shows the resulting traces 40, 42 of a short and a long carrier 32,respectively.

Another characteristic that can be altered in the mechanism is thedistance of the guide or slot 16 from the center of rotation of therotatable member or crank 22. As illustrated in FIG. 3, when all elseremains 'constant and the slot'16 is moved from a position intersectingthe center of rotation outwardly, the voli'ime enclosed by the traces 44and 46 increases as the distance of the slot from the center of rotationincreases. In addition there is a slight clockwise change of position ofthe trace with respect to the center of rotation as the slot distance isincreased.

The relationship between the length of the arm 10 and the diameter ofthe circle of rotation of the rotatable member or crank 22 is shown inFIG. 4. As can be seen, when the arm 10 is long relative to the diameterof the circle or conversely, the circle is small relative to the lengthof the arm the volume enclosed by the trace 48 of the mechanism issmall. When the arm is shortened the volume enclosed by the trace, as at50, increases while the shape of the trace remains nearly constant. Asit is the shape of the trace rather than the volume enclosed by' it thatachieves the desirable reading and writing characteristics, this is themost important consideration in the design of the mechanism. Althoughthe latter two variables (slot position and length of arm) only affectthe size of the trace, they are important in conforming the trace to thesize of the medium and thequantity of recorded information re uired bythe user.

n the examples descrlbedso far the guide or slot 16 has been disposed ina straight line, although there are a multitude of shapes the slot 16may assume and have acceptable results. A slot disposed in a curvedguide line 20, as illustrated in FIG. 5, achieves a trace 52 hav ing thedesirable characteristics heretofore described.

, Perhaps the most crucial of the relationships in determining the shapeof the resulting trace is the angle of the transducer carrier 32 withthe arm 10. As can be noted in FIGQG, when'all other-components'of themechanism are held constantand the carrier 32 rotated about its junctionwith the arm 10v there is a certain range of carrier angles which resultin markedly unsymetrical traces as at 54-60, while in another range ofcarrier angles the resulting traces 62-67 have more desirable elongated,symetrical shapes. A relationship has been found that approximates therange of angles at which the carrier 32 may extendfrom the arm 10 andproduce traces with desirable characteristics. When the pivot point 25of the arm 10 with the crank 22 is positioned on a center line 12 thatperpendicularly intersects the'guide line.20 through the center ofrotation of the crank 22, the desirable range of anglesis that 180sector on the opposite side of the center line from the junction of thearm with the slot 16.

The foregoing examples illustrate some of the many variations in whichthe present'invention may be embodied. The length of the carrier 32, theshape of the slot 16 and the distance thereof from the center ofrotation of the crank 22, the length of the arm 10 and the angle of thecarrier with the arm may all be modified in accordance with the teachingof the foregoingdescription in order to obtain a particular shape oftrace to suit a users need.

What is claimed is:

1. In apparatus for writing and reading data on and 1 from a magneticstrip, a mechanism for bodily transporting a transducer over a closed,elongated loop during the process of reading or writing, said mechanismcomprising: V r

a member rotatable about a stationary axis, guide 'means disposed on aguide line, said means being spaced apart from said rotatable member, anarm having a guided portion pivotally and slidably engaged with saidguide means for displacement along said guide line and a rotated portionpivotally coupled at a pivot point to said rotatable member, therotation of said member being operative in'imparting a reciprocal motionto said arm, said motion being characterized by the composite of themotions imparted to said rotated and said guided portions of said arm,and a transducer carrier joined to said arm at the rotated portionthereof for displacement therewith, said carrier having a mounting forsupporting the transducer, whereby the reciprocation of said arm conveysthe transducer mounted on said carrier in a closed, elongated loop. 2. Amechanism as defined in claim 1 wherein said carrier extends normallyfrom said arm.

3. A mechanism as defined in claim 2 wherein said carrier is at least aslong as said arm.

1. In apparatus for writing and reading data on and from a magnetic strip, a mechanism for bodily transporting a transducer over a closed, elongated loop during the process of reading or writing, said mechanism comprising: a member rotatable about a stationary axis, guide means disposed on a guide line, said means being spaced apart from said rotatable member, an arm having a guided portion pivotally and slidably engaged with said guide means for displacement along said guide line and a rotated portion pivotally coupled at a pivot point to said rotatable member, the rotation of said member being operative in imparting a reciprocal motion to said arm, said motion being characterized by the composite of the motions imparted to said rotated and said guided portions of said arm, and a transducer carrier joined to said arm at the rotated portion thereof for displacement therewith, said carrier having a mounting for supporting the transducer, whereby the reciprocation of said arm conveys the transducer mounted on said carrier in a closed, elongated loop.
 2. A mechanism as defined in claim 1 wherein said carrier extends normally from said arm.
 3. A mechanism as defined in claim 2 wherein said carrier is at least as long as said arm. 